ok so for my car i'll be having 15"x10 rears and 15"x8 fronts.

now i want the tyres to end up with a similar if not the same rolling diameter.

i was thinking..

 

225/60 15 and 215/60 15 but i can't seem to get the miata tyre size thing to work so i can't check it myself.

 

what would the experienced on here recommend?

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Thank me later :)

Edited November 17, 201015 yr by Raven

Yeah thats good but it doesn't allow to take tyre stretch into account!

why do you want 10" on the rear for?

 

i would just go 15x8 all round. then run the same tyre all the way around.

 

also stretch wont change you rolling diamter. its stretching the sidewall, not the tread part.

10s on the rear will cause more problems than it fixes. How much power are you planning on having?

How do you mean problems? I plan on having enough. 120 atw one day. But i want the maximum amount of grip i can get on my car so the 10 inch rear should provide that by allowing me to run a bigger tyre giving more rubber on the rd i can fit 10 inch under my guards so why not use it?

just my 2 bobs, but i think what everyone else is saying is right. 10's on the rear is overkill for 120 atw, in my honest opinion run 8's all round and just get some fatter tyres for the rear, give it the 'bagging' up look =)

120atw really isnt that much (i assume kw?)

 

most modded s13, r32, s15's go for 17x9's..and they have alot more than 120kw at wheels.

 

tyre brand/style is alot more important than tyre size.

 

get some 8" wheels, and some GOOD 205/50/r15 semi slicks (not $99 specials, toyo proxes R888's or simliar, most likely over $1000 for a set) it will grip a whole lot better than whatever you are going to fit onto a 10" wheel.

 

those proxies really are very good.

But in saying that are you telling me that the 8inch will out perform gripwise when cornering compared to a 10. The 10 will allow a wider tyre and give a larger contact area on the rd. So in the twisties which is what i have based my build around the 10 should provide more grip. I'm more than happy to be told otherwise by someone with experience in the matter.

Dave your makin a point there. But i'm after cornering more than straight line grip.

10 inch rears will promote understeer.

grip is grip man, the contact patch is the same.

 

those proxies just grip like nothing else, corners, braking, accel, you name it it will put your face through the windscreen. they also have a nice and stiff sidewall, good for giving you a sore back.

 

in theory yes a 10" wheel you can put 255's on and get better grip, but unless you have 400hp to turn them, there is no reason. the only cars that come standard with this size of tyre are ferraris, and they sure have alot more power than 120kw at the wheels.

 

and remember how light a corolla is (compared with said ferrari), in the corners you arent trying to turn alot of weight, a decent set of tyres will keep it going around the corner.

 

i recemently got a pair of federal 595's for the front of my ke70 (cheaper end of semi slick, like $148 fitted, 195/50/r15) and in the twisty stuff they just don't give in, grip grip grip grip untill the rear kicks out because I'm only running cheap sumotomo's (which arent that bad, but suck compared to the 595's). when the sumotomos wear out ill get another 2 595's. that will be very interesting.

Edited November 18, 201015 yr by ke70dave

10 inches aye? what sort of diff are you using?

The issues I see are fitment, as far as clearance of the car body. It needs room to move left and right as well as fit under. You are looking at 2 inch extension of the gaurd minimum if you have the ideal offset that goes within a half inch of the body on the inside.

 

If you run a mismatched tyre size you can create a few other handling demons such as understeer as stated above, and I personally think the car has more poise if it has equal levels of grip on all corners. You can neatly fit 8's on all corners in a neg offset that looks good and gives enough rubber. 10s are ok if thats what you want. Id prefer 10s all round with massive rubber over 8/10 if handling at all costs was required, but a 10 is a big ask of a standard ae86 stub axle which is the smallest size available. I just feel 8's are the right choice for the chassis, until you are looking at 500hp or more really.

ok so for my car i'll be having 15"x10 rears and 15"x8 fronts.

now i want the tyres to end up with a similar if not the same rolling diameter.

i was thinking..

 

225/60 15 and 215/60 15 but i can't seem to get the miata tyre size thing to work so i can't check it myself.

 

what would the experienced on here recommend?

 

Not sure if I'm that "experienced" but here's my 2cents. :)

 

At one stage i had 195/60/15s temporarily on the front of a KE70. you cannot run any decent amount of caster with this much rolling diameter unless you heavily cut/fold the front of the guards.

 

60 profile on a 15" is way too big. look at 50 series. This will also help to keep a similar rolling diameter to stock.

 

I wouldn't fit anything wider than 8-8.5" max (front or back).

 

I wouldn't go anything wider than 205(IMO 195) max width especially on the front. corolla's are light cars, no P/S and in your case you have a steering box. steering will be very heavy and slow in response with wider tyres. any sort of wet weather driving with wider tyres than this will make you aquaplane on bad roads.

 

I'd go probably 195/50s all round but maybe a 205 on the back if your end up with wider rims on the rear.

 

a quality 195 wide tyre can out grip a cheaper 225 tyre. I'd focus more on the quality of tyre you use.